1. Field of the Invention
The present invention relates to an apparatus for finishing slide fasteners by cutting off an elongate, substantially endless slide fastener chain across longitudinally spaced element-free gaps. The slide fastener chain which can be processed by the apparatus is of the type having a plurality of pairs of rows of coupling elements longitudinally spaced by the element-free gaps, at least one slider slidably mounted on each pair of the rows of coupling elements, and an end stop mounted on one end of the coupling element rows of each pair and engageable with the slider when the slider moves in a direction to interengage the coupling element rows.
2. Description of the Prior Art
Typical examples of prior slide fastener finishing apparatus are disclosed in U.S. Pat. No. 4,459,884, issued on Jul. 17, 1984 and U.S. Pat. No. 4,520,544, issued on Jun. 4, 1985. Each of the disclosed prior apparatus includes a cutting mechanism for cutting off the slide fastener chain across one of the element-free gaps to produce a slide fastener, a feed mechanism disposed downstream of the cutting mechanism for feeding the slide fastener chain along a path of travel, and a feedout mechanism disposed upstream of the cutting mechanism for feeding the slide fastener chain to the feed mechanism.
In operation, the feedout mechanism and the feed mechanism cooperate to feed the slide fastener chain downstream along the path of travel until an element-free gap of the slide fastener chain arrives at the cutting mechanism. Upon arrival of the element-free gap at the cutting mechanism, feeding of the slide fastener chain is stopped and the cutting mechanism is operated to cut off the slide fastener chain across the element-free gap. In order to position the element-free gap relative to the cutting mechanism and to stop the feed of the slide fastener chain, there is provided a chain stopper which is movable into and out of the path of travel of the slide fastener chain at a position immediately upstream of the cutting mechanism. The chain stopper is operatively connected with the feed mechanism and the cutting mechanism to control the operation of these mechanisms in a manner described below in brief.
As the slide fastener chain is fed by the feed mechanism, a leading one of the element-free gaps approaches the cutting mechanism. At this time, the chain stopper projects into the leading element-free gap. As the slide fastener chain further advances, a leading end of the succeeding pair of rows of interengaged coupling elements is brought into abutment with the chain stopper, whereupon the chain stopper detects the arrival of the leading element-free gap at a predetermined position in the cutting mechanism. With this detection by the chain stopper, the feed mechanism is stopped to terminate the advancing movement of the slide fastener chain, and the cutting mechanism is activated to cut off the slide fastener chain across the leading element-free gap to produce a slide fastener.
Since the leading end of each pair of rows of interengaged coupling elements is brought into abutment with the chain stopper, the row of interengaged coupling elements may be disengaged or separated from the leading end upon abutting engagement with the chain stopper. In order to avoid such coupling-element separation, the slide fastener chain must be provided with a bridge type end stop secured to the leading end of the coupling element rows of each pair. This type of slide fastener chain is illustrated here in FIG. 10 of the accompanying drawings, wherein bridge type end stops are denoted by ES6.
Accordingly, if the prior slide fastener finishing apparatus is used with a slide fastener chain FC1 shown in FIG. 7, the chain stopper cannot operate reliably because the slide fastener chain FC1 is provided with two pairs of separate end stops ES1, ES2 secured to the opposite ends of each pair of rows of interengaged coupling elements 111. Even if the rows of coupling elements of each pair is provided with a bridge type end stop at its leading end, the bridge type end stop is likely to be damaged due to concentration of force occurring when the bridge type end stop abuts on the chain stopper. This is because the chain stopper has a thin blade-like configuration in view of the necessity that it must be insertable in a narrow element-free-gap defined between a pair of opposed stringer tapes of the slide fastener chain.